Dovetailing attachment



Aug. 19, 1952 F. H. GILLESPIE ETAL DOVETAILING ATTACHMENT 6 Sheets-Sheet1 Filed July 31, 1948 Aug. 19, 1952 F. H. GILLESPIE ETAL 2,607,375

DOVETAILING ATTACHMENT Filed July 31, 1948 6 Sheets-Sheet 2 mllllm-"""FOREST fl. GILLESP/E if, a 4 HIQERV C. LUCRS a o DOM/MIC R M0771? BYM/VENTOES Aug. 19, 1952 F. H. GILLESPIE ETAL DOVETAILING ATTACHMENT 6Sheets-Sheet 3 Filed July 31, 1948 02557 H. amussp/z HHQEV c. u/cnsINVENTOQS Aug. 19, 1952 6 Sheets-Sheet 4 Filed July 31, 1948 E w w. w mmE N ummw o0. 7 O 0: W nW R 4 0m./ O: om W C mu L l wq mu www WW O E o ovv 6 1 1 9m N9 N2 om. Nmv wfi @u 8. in L M mu w mu mm mm 51- 5.- 2. Q.on. 02 mm9 m! mo. m3 :1 5 om. o! NE 91 om. F b v Q F 5 m. M m 8 m M onon W we 8 s J .l a Y @Q m m m M N! m@ L E Q we Aug. 19, .1952 F. H.GILLESPIE ET AL 2,607,375

DOVETAILING ATTACHMENT I 1 6 SheetsSheet 6 Filed July 31, 1948 FORESTG/LLESP/E DOM/N/C 1 M077 7 lA/l/ENTOBS QTTOQNES/ Patented Aug. 19, 1952Forest li. Gillespie'and Harry 0. Lucas, Los Angele's, and Dominic P.Motta, Glendale, Calif.; 7 said-Lucas and said Motta assignors to saidGillespie ce sar 3-1,194;saa111t,.41,134

The present invention relates generally to woodworking machines; andmore particularlyto an attachment for such machines whereby a series oftenons projecting from the end of a board or other work piece" may beformed to adapt the latter for attachment to another member having aseries of mortises formed therein.

' 'Mortise andtenon joints of the type abovedescribed are usually termeddovetail joints andare often used to attach the frontof a drawer to thesides thereof, the tenons being formed in the sides and the mortises.inthe front of the drawer. The mortisesfformed in such furniture partsare blind, that is, they do not extend through the front and are thusinvisible when the drawer is closed. Such mortises are formed with arotating dovetail cutter and thus are rounded at their inner ends.Accordingly, if a tight bond or glue joint is to be produced between thetenon and the mortise into which it fits, the tenon should preferably beformed with a rounded side adapted to fit into the rounded end of themortise. I Such mortise and tenon joints ar well known in the art andhave usually beenforr'ned by holding the two pieces in which. the[mortises and tenons are'to be cut, e. g., a drawer side and adrawerf1'ont,,together in a machine and at right angles to eachother', andbyaf single operation involving a plurality of rotating. cutters,

cutting the mortises in the one piece and the tenons in the other.Thereupon, the parts may be. removed from the maehineJand the tenonpiece reversed and placed interlocking rela I tion with the mortisedpiece. Such an arrange-'- ment is disadvantageous 'for'quantityproduction, however, in that the mortise and tenon pieces must be kepttogether andparticularly is it disadvantageous in the caseof drawerfronts since each sidepiece has one'set of tenons whereas the front hastwo sets of mortises j Machines have been designed in thepast in which aplurality of drawer sides, i. e'., piecesjin which tenons are to beformed, areheldin lback to-back relationship and sets of. tenons are'simultane'ously formed inthe two pieces. Such machines usually involvea plurality of rotating dovetail cutters and a movable work table towhich the work pieces may be clamped, and means to move thework'table'in an oval'path whereby 'a seriesof oval-shaped'projectionsare formed in'the end of the two pieces,' and..when the piecesareseparated, each has a series of the requisitely shaped semi-oval tenons.

12 Claims. (Clll l14 i- 8 7) f It is in a machine of the latter classthat e present invention is embodied. I A major object of the inventionis to'provide an attachment" for producing dovetail tenons which isfully automatic inits'oper'ation. I 1 I i Another object of theinvention is to provide a machine which requires nomanual manipulationthereof to produce the relative motion of the. work and cutters wherebyto promote uniformity in the-various parts produced.

,- I sen anotherobject is to providea maohinefof he character describedwhich is safe to operate, involvinga minimum of danger to operatinpersonneL'however inexperienced.

still anotherobject of the invention-is to a vide in such a machine,meansffor cutting' a complete dovetailed tenon which is adapted 'toImake intimate contact with the entire interior surface ofamortise'to'which it is assembledf" A further object of the invention isto provide in a machine of the class described for various adjustmentsto produce'dovetail tenons of various shapes, sizes and spacings. I IYet another object ofthe invention is toprovide dovetailing'means'in theform of an attaehment to a mortising machine where-by "to reduce thecost by eliminatingthe necessity for one entire. machine for producingtenons and another for mortices. Thefforegoing and other objects andadvantages 'of'the invention will be apparent from'a consideration ofthe following detailed descrip':

tion of a"machine embodying the same, such consideration being givenlikewise to the at- Figure 1'is aperspective view of a woodworkentinvention; v I I I Figure 2 is anenlarged perspective'view of a pair ofdrawer sides which have been operated on by the machine illustrated inFigure 1; I

Figure 3 is "a' fragmentary'top plan view of the woodworking machine ofFigure 1, showing in particular the dovetailing attachment;

I Figure 4 isan end'elevational view of the at.- tachment shown'inFigure 3; taken in thedirection indicated by the arrow 4 in Figure 3;

Figure am an enlarged elevational section taken on the line 5'5 inFigure 3; I

Figure 6 is an enlarged elevation'al section taken on the line 6-6 inFigure 3;

I Figure 7 is a fragmentary bottom plan view of the attachment inFigure'l; I I

Figure 8 is anenlarged fragmentary elevational view takenon the line 8-8in Figure 5;

Figure 9 is an enlarged 'elevational section taken on, the line'.9-9 inFigure 6;

Figure 10 is, an 'en ar e'dhorizonta'l section takenontheline Ill-10inFigure 5;

Figures 14 through 1'7 are diagrammatic views illustrating thesuccessive cutting operations repieces illustrated suiting in thefinished work in Figure 2.

General dasoription' The dovetailing attachment described herein isindicated generally throughout the drawings vention will be describedherein. Among such pertinent parts are banks 22 of rotary cutters 23 4elements of the attachment have been semischematically illustrated inorder to assist in visualizing the construction and operation of themachine.

W wk pieces "The particular work pieces 36 described in connection withthe operation of the invention herein are the sides of conventionalsliding drawers -used]in desks, bureaus, and similar J pieces offurniture. A shown herein, they have previously been-aformed with a pairof intersecting grooves 32, 33 which receive the back and the bottom ofthe drawer, res ectivel when the by the reference character 20, and ismounted 1n. p y

a multiple purpose woodworking machine 2|.

members 30 are assembled into a finished drawer. The series of spacedtenons 31 formed in the forward ends of the work pieces 36 will be seento be portions of ovoid conic frustrums, the larger end'of the conicfrustrurnbeing the outer end of the tenon 3i. Thus, it will be seenthat-each tenon 3| is adapted to enter a mortise 7 formedby arota'ryvdovetail cutter. In particuwhich'are' movably mounted betweenlongitudinal ways24, supported generally in a cabinet 25.

Two banks 22 of rotary cutters 23 are employed in the woodworkingmachine 2|, only one (that to the left in Figure 1) being employed inconnection with the attachment 20. The attachment itself includes:clamping mechanism adapted to grip and'hold a pair of work pieces withtheir ends projecting into the operating plane of the cutters 23.; amovable work table carrying the clamping mechanism; workmoving mechanismadapted to move a; table carrying the clamping mechanism and Work piecesin apath around thecutters 23 whereby to form a series of dovetailtenons 3| in the work pieces; and work-shaping means operating inconjunction with the work-moving mechanism whereby the shape of thetenons 3| is controlled.

' The entire attachment is mounted onthe'ways 24' by suitably shapedlips 26, and removably secured by dogs'27 which projectunderflon'gitddinal frame members 28 of the machine andare tightened bybolts 29 (see Figure 6) The attachment '20 is adapted for continuous Icyclic operation; each cycle, of which'startswith the work-movingtablein a stationary position, the complete cycle being as follows:

1. The clamping mechanism moves to acl osed V position'gripping the workpieces 30 and moving the same into operative engagement with the cutters23,,

2. The table moves in an ovoid pathv'vhe'reby each of theindividualc'utters 23 moves around a tenon 3|, forming the same,

3. The clamping mechanism opens, removing the completed workflpiecestflfrom operative enagement with the cutters '23, finally releasingthejsamewhereby' they maybe manually removed'fr'om the machine; N

Thusyit willbe seen that the operator of the woodworking machinej zlwith the attachment 20' therein merely places pairs of work pieces" 30in the clamping'mechaiiism of the attachment 20 and removes thesame'when the automatic'operation of the machine has formed the tenons3| therein. ,7 Y Y In Figures '11 through 13," the basic structuralClamping mechanism The details of the clamping mechanism are best seenin Figures 3, 4, 5 and 6. Here it will be seen that the work pieces 30are clamped in a vertical position between inner and outer vise jaws 4i)and 4|, respectively. As best seen in Figure 5, the vise jaws 40 and 4!are held in parallel alignment with each other and with the front faceof a supporting frame 42 by means -of'a pair of parallel rods 43 whichpass through these members adjacent the ends thereof. At the outer endsof the rods 43 (right in Figure 5),

a pair of knurled nuts 44 are threaded onto the.

rods whereby -inward "motion thereof pulls the outer vise jaw 4| towardthe supporting frame 42. The outer vise jaw 4| is fixed to the rods 43and is normally held in an outward or open position at the beginningpfeach cycle of operation of the attachment 20.

At the beginning of'theworkjcycle previously described, inward motion ofthe outer vise jaw 4i clamps thevvork pieces3ll against the inner viseja'w'40. "Aswill behoted from an examinatmnofFigure 5, theinne'r visejaw/40 is urged outwardly by a plurality of compression springs 45positioned in suitable recesses in the forward face of the supportingframe 42. Continued inward motion offthe outer visejaw 4! after theclampin'gof the work pieces 30"moves the inner vise jaw '40 inwardlytowards the supporting frame 42. The inward motion of the inner vise jaw40 permitted by the compression of the springs 45 carries the lower endof the innermost 1 work piece 30a into engagement with the rotatinplaceby a pair of bolts 43in the lower ends of vertical? extensions 49,the bolts 48 being with a central recess. 83,

threaded into framemembers 50 extendingfrom the bank 22 of cutters. .3

As best seen in Figure 8, an adjustable stop member and a, leaf spring52 serve to laterally position the workpieces 30 as they are droppedinto place between the vise jaws 40 The power to draw inwardly on theclamping rods 43- whereby to urge the vise jaws 40- together andthereafter move the work pieces 30 into the cutters 23 is supplied by ahydraulic cylinder 55 mounted above the clamping mechanism (Figure 3)and having a movable piston therein operating through a piston rod 56with a clevis=51 on the outer end thereof. A crank arm 58, pivotallyconnected at its outer end to the clevis 51, serves to rotate a rock"shaft 59 each time the hydraulic cylinder 55 is actuated. It will benoted that the cylinder 55 is pivotally attached by a bracket 60 at itsrearward end whereby to permit the entire cylinder 55 to swing sidewaysslightly to accommodate the arcuate motion of the'outer end of the crankarm 58.

A cross link 6|, pivotally connected by a bolt 62130 an intermediatepoint in the crank arm 58, serves to cooperatively connect the crank arm58 toa short crank 63 keyed flto a forward rock shaft64. Thus, eachactuation of the hydraulic cylinder 55 results in simultaneous swingingmotion of the cranks 58 and 63, and therefore simultaneous rotation ofthe two rock shafts 59 and 64.

At the lower ends of the rock shafts 59 and 64, cranks 66 are securedthereto as best seen in Figure 5, the cranks 66 being provided withcrank pins 61 operating through connecting rods 68 to actuate theclamping rods 43,- the latter two members being pivotally connected by awrist pin held in a suitable boss H formed in the rearward end of eachof the clamping rods 43.

Hydraulic fluid connections 12 and I3 at the ends of the cylinder 55serve to connect flexible conduits I4 whereby 'hyraulic fluid isdelivered to and from the ends of the cylinder 55 in order to actuatethe piston therein. The delivery of hydraulic fluid to the piston 55 iscontrolled by a timer (not shown) so that at the beginning of each workcycle, fluid is delivered to the inner end of the cylinder through theconnection I3 and from the cylinder through connection 12 whereby to'thrust the piston rod 56 outwardly,

rotating the cranks 58 and 63 counter-clockwise :(inFigure 3) and fromthe arrangement of the lower cranks 66, it will be seen that suchcounterclockwise rotation draws inwardly on the rods 43 to close thevise jaws404|. At the end of the work cycle, the direction of fluid flowisreversed, and fluid is introduced through the outer fluid connection12 to draw inwardly on the piston rod 56 whereby to operate through theabove described linkage to open the vise jaws 40-4I, permittingwithdrawal of the finished work pieces 30.

Table i As is best seen in Figure 5, the entire clamping mechanism ismounted by means of bolts 80 to a flat work table 8|. The work table 8|in turn rests on a bed plate. 82 which is formed whereby the table 8|bears only at its edges-on the upper surface of thebed plate 82. Spacedabove the upper surface of the bed plate 82 by spacers 84 is a holddownplate 85 which functions to slidably retain the. table 8| against thebed plate 82. The thickness of the spacers 84 is very slightly greaterthan the thickness of the table 8| where by thelatter may slide in anydirection in the plane of the bed plate surface In Figure 6, it-will benoted that the sides of the bed plate 82 are spaced from the spacers 84whereby lateral motion" of the table is permitted andin Figure 5 it willbe seen thatthe table may also move longitudinally, slidingflon the bedplate'82.

vTransverse strips 86 of felt or other similar material bear against theunder surface of the table. 8| to seal off an interior cavity 81 inwhich is located'the work-moving mechanism, laterv to be described. Thestrips 86 are secured in place by means of brackets 88. I A

The hold-down plate 85 is formed with an upstanding wall 90 adapted toreceive a cover plate 9| whereby to enclose the'work-guiding mechanism,later to be described.

Work-moving mechanism It will be remembered that, during the operationof cutting the tenons .3I,. the. clamping mechanismand the work pieces30 carried thereby is movedliina curved pathwith respect to the cutters23.-. This movement is accomplished in the present machine by means ofparallel and coordinatelyv moving cranks I00. The cranks I00 arevertically disposed in side-by-side. relationship, as shown in Figure 6,and each comprises a main shaft IOI journalledin. a pair of .radial ballbearings I02 and I03, a crank arm indicated generally by the referencecharacter I04, and a crank pin I05. Each of the crank pins I05 isrotatably secured in the table 8| by means of a radial ball bearing I06.Accordingly, concurrent rotation of the two cranks I00 results in an.oscillatory motion of the table 8| carrying the work pieces 30 in a patharound the cutters 23. By virtue of the fact that .two cranks are used,the clamping mechanism and the work pieces 30 held thereby are at alltimes during the oscillatory motion parallel to the initial startingposition.

Each of the crank shafts |0| has keyed to the lower end thereof a pinionH0, and the pinions IIO are in common mesh with a sectorv gear III. Thesector gear III islocated under the bed plate 82 and is pivotallycarried by a downwardly extending shaft ||2 fixed in the bed plate.-

Thus, it will be seen that when the sector gear I II is rotated ineither direction about the pivot shaft H2, concurrent rotation of thecranks I00 is produced. The number of teeth in the sector gear III issufficient so that swinging the latter in one direction or the otherfrom one limit of its position to the other limit thereof produces a 360rotation of each of the pinions H0, and

' hence of the cranks I00.

. Power to move the sector gear III as above stated is produced througha pivotally mounted hydraulic cylinder II5 (Figure 7) having a pistonrod- I I6 with a clevis I H on the forward end thereof.

Inward or outward motion of the piston rod I I6 is transmitted to thesector gear III through a double arm crank II8 pivotally mounted to thebed plate 82 and a connecting rod I I9 connected by a pivot pin I20 tothe sector gear III at a point spaced from the centerof rotationthereof.

As with the hydraulic cylinder 55 in the clamping mechanism, thework-moving cylinder H5 is provided with fluid connections I2I and I22to move the clevis II I inwardly or outwardly.

' such motion into As above stated, a single. stroke of .the clevis .I Hin either direction is sufiicient to rotate the pinions through 360 andto thereby complete one cyclic motion of the table BI and the clampingmechanism and workpieces carried thereby. Thus on one work cycle, theclevis II'I moves outwardly of the cylinder H5 and. on the nextsucceeding work cycle moves inwardly thereof, and so on, alternately'inone direction .or the other. The alternateemotion of the vclevis If?just .described results in .alternate clockwise-and counter-clockwiseoscillatory motion of. the work table during succeeding work cycles, but:it is obviously immaterial which direction the work moves around thecutters 23 in producing the tenons 3|. V

Work-guiding mechanism It will be realized that if the cranks I wereconventional, having a fixed throw, the result would be to move the workpieces 30in acircular path around the cutters '23. It will beremembered, however, that. a semi-oval shaped tenon is required ratherthan a semi-circular tenon. Thus, it is necessary to change or. guidethe-circular motion ofthe crank'pins I05 to distort an oval path ratherthania circular path. 7

This distortion of 'thenpath into 'the"desired 'oval movement isaccomplished by making the throw or axial 'displacementzof. the crankpins I05 variable during the work cycle, and providing'gu'i'de means bywhich this throw is adjusted during the work cycle to produce anovalpath. To provide the adjustable throw just described, the crank arm I04is made in two separate and relatively slidable parts; the lowermost 130being formed as part of the crankshaft [0i and having a dovetail'wayformed therein, as can be seen in: the right-hand crank-in Figure 6. Theuppermost crank arm member I3I is shaped for a sliding fit in the wayof' the lower-crank arm portion I and an adjustable .gib I32 (seeFigure. 6) is provided whereby to take up for wearin'the way. The crankpinI05 is :fixed in the movable crank arm portion I3I.

Thus, it will be seen'that, as the movable crank arm portion "I3! slidesback and forth'in the wayv of the fixed portion I30, thefdisplacement ofthe axis of the crank pin I05. with respect to the axis ofthe crankshaft IOI 'is'varied. Each crank arm is provided with a pair ofcompression springs .133 anchored against :an end cap I34 and thrustingagainst the movable crank arm portion I3I whereby to 'urge the sameoutwardlyfviz, in-- a direction to increase the throw of the crank.

In order to limit the. outwardm'otion of the crankpins I05 urged-by thespring :I33,-'.the crank pins 105 are extendedupwardly beyond the uppersurface of the movable table 8 I and each carries, rotatably mountedthereon; a itapered roller I40. Each of the rollers I 40 be'ars'againstan inner curved track in' a cam' or 'jig jig plates I4I' arelo'cated withinthe enclosure formed by the upstanding wall :90 andarer'emovably secured to the hold-down plate 85 by means of bolts5i42.

Each jig plate' I4I is coaxially -positioned with respect to one of the'crank shafts IOI,"and as can be'seenbest in Figure 3, 'the interiortrack M3 is'ovoid in shape, thus guiding the roller'and as a'ccnsequencethe crank pin I05 inf an pval path'around the axis-of the crankshaft-40L ing mechanism. Such adjust theisize of the oval'path followedby the roller I40 is illustratedfin- Figure 9. Here'it will be seen thateach roller Hill. is rotatably carried by the crank pin I05 on lowerand-upper radial ball bearings I and 146, respectively. It will be notedfurtherthat the recess'in the roller I40 inwhich the lowerradial bearingI45 is received is somewhat deeper than the width of the hear-,- ing,thus making possible vertical motion of the roller I40 with respect, tothe bearing I45... It will be noted also that the ,cam-track-contactingface -;I 41 is tapered and is somewhat. wider. than the face of the camtrack I43. ,Thus the roller I40 may be moved upwardlyor downwardly;decreasing. or increasing thehefiective diameter thereof,.andconsequently increasing ordecreasing the diameter of the oval-pathfollowedaby the roller; Means *for effecting upward and downward .motionof the roller M0 to change the effective diameter thereof is providedby-anchoringthe inner race. of the upper bearing I46 to a hexagonallyflanged bushing J50 threaded onto an extension of the'crank' pin I05 andan? chori-ng the outer:ra'ce of the bearing I46 into its recess in theroller I40. Such anchorage of the races of the bearing I45 is providedby means of snap rings I5I and I52, respectively. It'will be seen,therefore, that'rotation of the bushing I50 on the threaded extension ofthe crank pin I05 will movethe roller upwardly or downwardly. A lookscrew I53 anda washer-I54 serveto-lock the bushing I 50 in anyadjustedposition'thereof. .:iWhenever it is desired to. remove-thezjig platesI4I, for example, when changing the size of tenons 3| cut in theworkpieces 30,itis necessary to relieve the outwardly. thrusting pressure ofthe roller 140 against the cam tracks I43. For this purpose, aneccentric member I '60:.is mounted on the rear uppersurface of the tableBIby-means of a'bolt 1'61. -When it is desiredito remove the ,jig platesMI,- the member I60. may be rotated by'means of aspanner wrenchholetherein :tov bear against the rear surface of the upstanding. wall 90.Such rotation of the. member. Hit-forces the table 8I' rearwardly, andthus (when the machine-is in the stationaryposition illustratedinFigurefi) moves the rollerI40 rearwardly away-fro'mthe-cam track 'I 43compress.- ing the springsyI-fisinthe crank arm "I04.

During operation of the attachmentxdescribed herein, thecover- 9|.1isleftin placeon the wall whereby to prevent dust, shavings, andxso forth,from entering the enclosure thereunder and possibly interfering with'theproper action of the rollers I40. 1

' Operation The successive operations of .the clamping V of the worktable are timed or programmed by a plurality ofhydrau lic valvesoperated sequentially by suitable timtiming :or programming mechanismsare well-known in connection with automatic hydraulic machineryand forthisreaison no detailed"description'thereof is deemed to ageovga'zs benecessary herein. Suflice it to say, that each of the hydraulicconnections of the two hydraulic cylinders 55 and l ['5 is provided witha solenoid valve which valve is in turn actuated by a time switch at theproper point in the sequence of operations. 1 J i Figures 14 through 17show the successive relative positions of the cutters 23 and the workpieces 30 which ultimately result in the formation of the tenons 3|. Itwill be realized, of course, that the motion of the work pieces '30around the cutters 23 can be considered as relative,' and the operationcan be equally well described by referring to the motion of the cuttersaround the work pieces'3lL' r Figure 14 illustrates the relativeposition of the work pieces 30 and the cutters 23 at the start or restposition, wherein the work pieces 30 have just been introduced betweenthe vise jaws 40 and 4|, and just prior to the closing of the vise jaws.Figure 15 illustrates the relative position after the vise jaws haveclosed, and it should be noted that the cutters 23 have slightly enteredthe innermost work piece 30a. This initial cutting action of thecutters. 23 is important by reason of the fact that the tenons 3| to beformed are tapered and that if initial longitudinal motion were notprovided for, the tenons would have flat spots on them adjacent thesurface of the inner workpiece 3012.

After the initial longitudinal motion effected by the operation of theupper hydraulic cylinder 55, the timing mechanism operates to deliverhydraulic fluid to one end of the lower hydraulic cylinder I I5,simultaneously releasing the fluid from the other end of that cylinder.This results in a stroke of the clevis H1 which,'as previously stated,operates through the sector gear II I, the pinions I In, the cranks I00and the table 8 Iv to move the work pieces in an ovoidpath around thecutters 23 to form the tenons 3| therein. The end or completed positionis illustrated in Figure 17,'and it will be realized that the openingoperation of the vise jaws 4fl4| at this point serves to move theworkpieces 30 away from the cutters 23 and permit withdrawal thereof. i

The arrows in Figures 16 and 17 illustrate the relative motion of thecutters 23 through the work pieces, although it will be realized thatthe latter members are actually in motion while th cutters arestationary.

The cutters 23 being located under the clamping mechanism and behind theshelf 46,it is virtually impossible for an operator to inadvertentlycome in contact with the cutters 23 and be injured thereby.

Whenever it is desiredto remove the attachment from the woodworkingmachine 2|, in order that the latter may be used for other purposes, theremoval is quickly accomplished by loosening the clamping bolts 29,suitable apertures 29a being provided in the bed plate to give access tothe clamping bolts.

The attachment illustrated and described herein has been found toproduce great uniformity in the tenons produced, due to the fact that,upon each successive operation, the cutters move at exactly the samespeed through the work and are always guided in exactly the same path.Such automatic operation provides a considerable-advantage over previousmachines which are manually operated, and wherein the uniformity of thework depends on the operator applying exactly the same force to move thework through the cutters and guiding the work in thesame path each timethe machine is operated.

The'prese'nt attachment is capable of forming a wide variety ofdifierently shaped parts by interchangingthe jig plates I41, specialprovision having been'made to simplify this operation,

- While the attachment shown and described herein is fully capable of--achieving" the objects and providing theadvantages hereinbefore stated,it will be realized that it is capable of'considerable modificationwithout departing from the spirit ofthe invention. For this reason, wedo not mean to be limited to the form shown and described, but rather tothe scope of the appended claims. r We'claimz 1". In a woodworkingmachine: a power driven cutter; support structure including a tablesupported" for curvilinear ,movement in a given plane; clamp meansmountedo'n said table adapted to grip a work piece andmovethe same intoinitial cutting engagem'ent'with saidcutter; drive means to move saidtable in said plane whereby to efiect'relative movement of said cutterthrough said'work piece, said'drive' means including a pair ofconcurrently rotating cranks, each having an adjustable throw and acrank pin projecting through said table and journalled therein; and cammeans to guide said table whereby to produce a predetermined shape ofcut in said work piece, said cam means including .a pair of cam'tr'ackmembers mounted in fixed position adjacent said table and followers onsaid crank pins in engagement with said cam tracks whereby the throw ofsaid cranks is varied during rotation thereof.

2. In a woodworking machine: a power driven cutter; supportstructureincluding a table supported for curvilinear movement in a givenplane; clamp means mounted on said table adapted to grip a work pieceandmove the same into initial cutting engagement with said cutter; drivemeans to move said table in said plane whereby to effect relativemovement of said cutter through said workpiece; and cam means to guidesaid table, said cam means including a pair of spaced apart inv saidplane and substantially identical non-circular cam track members and apair of followers connected tosaid table and each'in engagement with oneof said cam track members whereby to produce a predetermined shape ofcut in said work piece.

3. In a woodworking machine: a plurality of vertically disposed dovetailcutters arranged side-by-side in a straight line; support structureincluding a pair of fiat horizontal spaced parallel plates and a tableslidably held therebetween for curvilinear movement in-a planeperpendicular tothe axis of said cutters; clamp means mounted on saidtable and having a pair of movable spaced jaw members adapted to moverelatively toward each other to grip a work piece therebetween with alower end thereof adjacent said cutters and thereafter move in unison,said clamp means including power means to move said jaw members to firstclamp said work piece and thereafter move the same into initial cuttingengagement simultaneously with all of said cutters; workmoving meansincluding at least one adjustable-throw crank having a pin journalled insaid table and means including a drive member in engagement with saidcrank to rotate the same to move said table; and guide means includingan internal cam fixed to one of said plates adjacent said crank and afollower on said crank pin engaged with said cam whereby with respect tosaid cutter ;,a pair of-reciprocable tension rods perpendicular to saidface and :pro- ,iecting therefrom; a 'first *ja-w' member connected totheouterends of said IOdS SitidfilSb jaw member being parallel to saidface, a' second jawmember slidably mounted onsaid-rods and paralleltosaid-first jaw member'and spaced therefrom; compression spring means:positioned between said face and said second jaw member to normally holdthe latter away fromr'said "face; a pair of crankskjournalled in saidsupport member; a link member interconnected betweenusaid cranks -to;effect concurrent rotation :therieof; a pair 'of connecting. :rodseach-connected between one of said tension rods and-one. of said crankswhereby rotation of'saidacranksmoves said;t'en+ sion rods in unisonselectively toward cor. away fromsaid face; and power means 'inc'ludingahydraulic cylinder and piston rod Iconnectedto one of said crankswherebytto actuate the same to' selectively 'move :said tension. rodsinwardly to clamp a work piece-betweentsaid jawmembers and thereafter.move the same into cuttingengagement with said tcutters'," compressing:said spring means, or .to 'move saidztension rods outwardly ,to releasesaid work piece.

-5. Ina woodworking machine of the type having a movable worksholdingclamp and are" tatingcutter, means to move said-clamp in a predeterminedpath with respect to said cutter whichtincludes:'movable table meanssupporting said clamp; a pair of spaced apart cranks each havin'gxa pinjournalled in said table means; means to'concurrentlyrotatesaid cranks;and means to guide the movement'of said pins in noncircular paths.

6'.-In a. woodworking machine of the type-having a movable work-holdingclamp and a rotating cutter, means tomove said clamp in-a predeterminedpath withrespect to said cutter which includes: movable tablemeans-supporting-said clamp; a pair of spaced apart cranks,'eachhaving'an adjustable throw: and a pin projecting through said tablemeans and journalled therein, each of said pins havinga portionprojecting beyond the plane of saidtable; means to 'concurrently rotatesaid cranks; and a pair of fixed,

non-circular cam track members engaged with said-projecting pin portionswhereby toguide' themovement of said'pins in a non-circular path.

77.. Ina .woodworkingmachine of the type-having a movable work-holdingclamp and a rotating cutter, means to; move said clamp in apredetermined path with respect to said cutter which includes: movabletable means supporting said clamp; a pair. of spaced apart cranks, each'of said cranks'having an adjustable throw and a crankpin journalled insaid table means; means to concurrently rotate saidcranks; spring meansin'each of said cranks to urge said pins in a throw-increasingdirection; and non-circular cam track means engaged with each of saidpins and adapted to restrain said throw-increasing movement thereofwhereby to guide said pins in anon-circular path-upon rotation of saidcranks.

8. In a woodworking machine of the type having a movable work-holdingclamp and a rotat ing cuttenmeans to move said clamp in a predeterminedpath With respect to said cutter 12 which includes: a flatjtable,supporting: said clamp; .5 said table; being' supported -;forl slidingcurvilinear .motiona in a, 1 plane perpendicular ;to

said cutters" a pair; of substantially identical cranks, each havingv arotatably, mounted main shaft perpendicularto the plane of saidetable,

a, telescoping; arm: adapted to change. thew-throw of'said-crank; acrank vpin in said arm, aspring in: said arm normally urgingextensionithereof to increase the throw of. said crank, said prank pins .bei-ng journalled in .said: tab1e-.whereby' to effect: parallel. motion ,of'said-stable upon .urotas tion; of; said: cranks, each of said pinshaving :a portion rprojecting beyondss'aiditable; means. in: cluding adrive member;impommon driving:en+ gagement with: said cranks: ;to' 1concurrently. mtate the same and a pa irxof non-circular camtraoklmembers, one: mounted .in vfixed position adjacent .ieachmf :saidj:cranks and in; engage:- ment with said" projacting. pinportiontwher'ebv to.v restrain? said spring-urged .'.extension. of :saidcrank arms: and guidezsaidjcrank pins -in T1011: circular paths".

9. In a woodworking machine. of the .typehaving ,a movable: Workholding. clamp and a .rotate ing cutter, me'ansto move saidclamp in apre-- determined path with respect to said cutter. which includes-:1movable :tablemeans. supporting. said clamp; a crankhaving anadjustablei throw and a pin journaled in said table. meansfmeanstorotate'sa'id crank; a cam. having-aguide surface-disposed substantially.in a: given plane, fixedwith respect to :said:table, and positionedadjacentithereto; and a follower mounted on said .tabl'e' projectingtherefrom, and. being. engaged Withisaid guide surface whereby to guidesaidtable in a predetermined path "as. said :crank is. rotated.

10,v The construction of claim 9 further characterized inythatsaidfollower .is tapered along an axis; substantially. pe'rpendicular'to theplane of saidrguide surface-, and selectively movable alongsaid axistoadjust theclength of said path.-

ll. The constructionzof claim lO further characterized in:that.saidafollower, 'is'a tapered roller rotatablyimo'unted on an axis fixedwith-respect to said table.

12.:Inza woodworking machine of the type having azmovablework-holdingclamp .and a rotating cuttensmeans to move said clamp in: a'predee terminedpath with respect to said cutter which,

"REFERE CES CITED The following references .are ofrecordin the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,694,115 Bottcher Dec. 4, 19281,860,660 Dart May 31, 1932 2,225,263 Farrell i Dec. 17, 1940 2,260,662Farrell-r", Oct.- 28, 1941 2,299,602 Teague Oct. 20, 1942 2,314,179Teague Mar. '16, 1943

